Caption: Neutrino particle detector. Computer artwork of neutrinos (red lines) passing through the Earth and being detected by the Antarctic muon and neutrino detector array (AMANDA, bottom), a neutrino telescope situated beneath the Amundsen- Scott South Pole Station. The inset shows a neutrino colliding with a water atom in one of AMANDA's optical modules. The modules detect radiation given off when neutrinos passing through the Earth from the Northern hemisphere collide with the nuclei of oxygen and hydrogen atoms in the water ice, producing a muon and a hadronic shower. By analysing the timing of photon hits the optical modules can determine the direction of the original neutrino. AMANDA is used to identify and characterise extra-solar sources of neutrinos.